Imaging forming apparatus and copy management system

ABSTRACT

An additional data useful for the management of copies of a document for an image forming apparatus is embedded in a hard copy of the document. The additional data is embedded in an inherent image of a document as discrete dots arranged in a prescribed format. Preferably, the size of each of said discrete dots is not so large as to be recognized easily with naked eyes. The additional data can be embedded in unit of blocks. Further, the density of the discrete dots is different from the density adjacent to the discrete dots. The image data for embedding an additional data can be obtained by reading a document, or by receiving data sent from a computer or read from a floppy disk. An additional data embedded in a hard copy can be extracted from the image data on the hard copy. Further, the production of a copy according to the image data can be controlled according to the extracted additional data. For example, if the additional data means that the source of the hard copy is a secret document, the copying is allowed only for a legitimate user. An additional data is generated for each copy according to the extracted additional data for embedding it in a hard copy to identify each copy. The additional data generated for each copy are compiled and they are used to manage copies of various sources systematically and illegal copies can be traced easily. If the additional data received from a printer is not consistent with the additional data already stored, the printing may be prohibited. A transmitter for transmitting an additional data may be provided in a document such as a book.

RELATED APPLICATIONS

[0001] This application is a divisional application of copendingapplication Ser. No. 08/911,101, filed Aug. 14, 1997, which is adivisional of application Ser. No. 08/327,223, filed Oct. 21, 1994, nowU.S. Pat. No. 5,671,277 issued Sep. 23, 1997, which is a continuation ofapplication Ser. No. 08/084,408, filed Jun. 29, 1993, now abandoned,which claim priority from Japanese Patent Application Nos. 4-172617,filed Jun. 30, 1992, 4-172621, filed Jun. 30, 1992, 4-172659, filed Jun.30, 1992, 4-172672, filed Jun. 30, 1992, and 4-172680, filed Jun. 30,1992.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an image forming apparatus suchas a printer or a copying machine for producing a copy and a managementsystem therefor which can prevent illegal copy.

[0004] 2. Description of the Prior Art

[0005] Recently, copying machines are developed and used widely. Then,infringement of copy right and illegal copies of secret documents becomeproblems to be solved. However, it is impossible for analog copyingmachines to check an original document precisely. Further, for adocument including a partial copy, it is quite impossible to manage hardcopies after the second generation of copy of the original document.

[0006] There have been proposed many apparatuses and methods in order toprevent the leakage of secret documents by copying. For example, if acopying apparatus detects a phrase registered beforehand such as “DO NOTCOPY” or “CONFIDENTIAL”, the copy operation is stopped (Japanese Patentlaid open Publication 266,759/1990). However, an illegal copy is easy bycopying a document by shading the registered phrases. Therefore, if acopy is once obtained by shading the registered phrases, it cannot beprevented to be leaked. It is also disclosed that an illegal copy can bedetected by using information on the characteristics of a document onthe image of the whole document such as the position and the number of aspecified character such as “u”. However, this requires a memory oflarge capacity to store all characters.

[0007] In order to prevent illegal copies of paper moneys and valuablesecurities with a copying apparatus, it is proposed to store a patternof characteristics of an image for prohibiting copying and to stop thecopying operation for an image of a document including such acharacteristic (Japanese Patent laid open Publication 52,384/1990). If awhole document image is stored as a characteristic pattern, this copyingmachine can deal with even a case where a part of the characteristicpattern is shaded. However, in order to store all characteristicinformation for a secret document, a memory of large capacity is neededalso in this case. Further, it is difficult to detect all information incorrespondence to copying operation.

[0008] It is also proposed that a password is needed for a copyingapparatus (Japanese Patent laid open Publications 120,753/1990 and120,561/1991). However, it is a problem that a password is needed evenfor a non-secret document.

[0009] On the other hand, in order to trace the origin of leakage of asecret document, it is proposed to add information to a part of a copyof a document (Japanese Patent laid open Publication 111,161/1990). Thatis, information such as recognition data of a copying apparatus, copydata and copy time are expressed as bar codes, and the bar codes areadded in a part of a copy. However, this approach is ineffective if thebar codes to be added in a copy is shaded or if bar codes added foranother non-secret document is stuck to a copy to re-generate the copy.

[0010] It is also proposed to change a font for a secret document fromthat of an ordinary document in order to recognize a copy of secretdocument from the others (U.S. Pat. No. 4,837,737). Then, even if thecopies of secret documents are edited or changed, a copy of a secretdocument can be recognized. However, this approach is ineffective if adocument includes only drawings, graphs or the like.

[0011] The synthesis of character data with an image data in the imageprocessing with a computer is proposed (Yasuhiro Nakamura and KineoMatsui, “A unified coding method of image and text data usingthree-level micro-patterns”, Gazou Densi Gakkaishi Vol. 17, No. 1 (1988)3-9). In the image processing wherein the sum of the dots in a smallarea of n×n dots is used as a density of a dot to be displayed, apattern corresponds with a density, and text data are synthesized withan image data by using the patterns. However, if this approach isapplied to a copying machine, it is impossible to recognize the patternsin a hard copy. Therefore, this approach cannot be applied to trace theleakage of secret documents.

SUMMARY OF THE INVENTION

[0012] An object of the present invention is to provide an image formingapparatus which can prevent an illegal copy effectively.

[0013] Another object of the present invention is to provide an imageforming apparatus which can detect an illegal copy effectively.

[0014] A further object of the present invention is to provide a copymanagement system which can manage copies to detect and to prevent anillegal copy.

[0015] In one aspect of the present invention, an additional data usefulfor the management of copies of a document produced by an image formingapparatus is embedded in a hard copy of the document. The additionaldata is embedded in an inherent image of a document as discrete dotsarranged in a prescribed format. Preferably, the size of each of saiddiscrete dots is not so large as to be recognized easily with nakedeyes. The additional data can be embedded in unit of blocks. Further,the density of the discrete dots is selected to be different from thedensity adjacent to the discrete dots. The image data for embedding anadditional data can be obtained by reading a document, or by receivingdata sent from a computer or read from a floppy disk.

[0016] In a second aspect of the present invention, an additional dataembedded in a hard copy as mentioned above can be extracted from animage on the hard copy. That is, the image data includes an additionaldata embedded in the inherent image as discrete dots arranged in aprescribed format, and it can be recognized and extracted. Further, animage forming means for producing a copy according to the image data canbe controlled according to the extracted additional data. For example,if the additional data means that the source of the hard copy is asecret document, the copying is allowed only for a legitimate user.

[0017] In a third aspect of the present invention, an additional data asmentioned above is generated for each copy according to the extractedadditional data. Then, the generated additional data is embedded in ahard copy. Thus, each copy can be identified.

[0018] In a fourth aspect of the present invention, a management meansstores the additional data generated for each copy produced in aplurality of printers and the like. Thus, copies of various sources canbe managed systematically and illegal copies can be traced easily. Ifthe additional data extracted from an image in a hard copy is notconsistent with the additional data already stored, the printing of thehard copy may be prohibited.

[0019] In a fifth aspect of the present invention, a document such as abook includes a transmitter which transmits an additional data of thedocument wireless. The additional data received is used to control theimage forming means.

[0020] An advantage of the present invention is that the situation ofcopying can be grasped according to the additional data. For example,the total copy number from the same original document can be countedeasily.

[0021] Another advantage of the present invention is that an additionaldata for managing copies can be embedded in an image of a documentwithout deteriorating the reproduced image substantially.

[0022] A still another advantage of the present invention is that anillegal copy such as a copy of a secret document by an non-legitimateuser can be detected according to the additional data extracted from thecopy.

[0023] A further advantage of the present invention is that the leakageof a secret document can be prevented.

[0024] A still further advantage of the present invention is that anillegal copy can be detected even if a document is edited.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] These and other objects and features of the present inventionwill become clear from the following description taken in conjunctionwith the preferred embodiments thereof with reference to theaccompanying drawings, and in which:

[0026]FIG. 1 is a block diagram of a hard copy management system;

[0027]FIG. 2 is a diagram of an example of generation codes of hardcopies embedded in hard copies;

[0028]FIG. 3 is a diagram of an example of copy code;

[0029]FIG. 4 is a diagram of an example of binarized data of additionaldata to be embedded in a hard copy;

[0030]FIG. 5 is a diagram of an example of the binarized data dividedinto data of variable length;

[0031]FIG. 6 is a diagram of an example of block data of block number“1” and “65” when binarized data of an additional data is divided into8-bit data;

[0032]FIG. 7 is a diagram of an example of density data of block data ofblock number “1” embedded in an image;

[0033]FIG. 8(a) is a diagram of an image of a character “a” embedding ablock data;

[0034]FIG. 8(b) is an enlarged view of the lower right-hand section ofFIG. 8(a);

[0035]FIG. 8(c) is an enlarged view of a portion of FIG. 8(b);

[0036]FIG. 8(d) is a numeric representation of the data bits shown inFIG. 8(c);

[0037]FIG. 9 is a diagram illustrating a procedure for embedding blockdata of the additional data in a hard copy by using density blocks;

[0038]FIG. 10(a) is a diagram of an example of an image of a documentconsisting of various densities wherein additional data is embedded;

[0039]FIG. 10(b) is an enlarged view of the right-hand section the imageshown in FIG. 10(a);

[0040]FIG. 11(a) is a diagram for changing the density of a documentimage when the density of the document image changes continuously;

[0041]FIG. 11(b) is an enlarged view of the area designated by the boxin FIG. 11(a);

[0042]FIG. 12(a) is a diagram of an example of a process of embeddingadditional data for a document image wherein a long data cannot beembedded continuously;

[0043]FIG. 12(b) is an enlarged view of the middle section in FIG.12(a);

[0044]FIG. 13 is a block diagram of a processor which also illustrates amain flow of data;

[0045]FIG. 14 is a block diagram of an image read section;

[0046]FIG. 15 is a block diagram of an image read section and a codedata read section in the image read section;

[0047]FIG. 16 is a flowchart of the processing of the image readsection;

[0048]FIG. 17 is a block diagram of an operational section;

[0049]FIG. 18 is a block diagram of a packet analysis section;

[0050]FIG. 19 is a diagram of a format of image data received from acomputer;

[0051]FIG. 20 is a block diagram of packet analysis section;

[0052]FIG. 21 is a block diagram of floppy disk analysis section;

[0053]FIG. 22 is a diagram of a format of image data received from afloppy disk;

[0054]FIG. 23 is a flowchart of the processing of the floppy diskanalysis section;

[0055]FIG. 24 is a block diagram of image decision and recover section;

[0056]FIG. 25 is a flowchart of the processing or the image decision andrecover section;

[0057]FIG. 26 is a flowchart for providing numerical data ofcharacteristic points;

[0058]FIG. 27 is a flowchart of the recovery of additional data;

[0059]FIG. 28 is a block diagram of an additional data managementsection;

[0060]FIG. 29 is a flowchart for embedding new additional data in theadditional data management section;

[0061]FIG. 30 is a flowchart of the generation of data to be embedded;

[0062]FIG. 31 is a block diagram of a main controller;

[0063]FIG. 32 is a flowchart of the processing of the main controller;

[0064]FIG. 33 is a flowchart of hard copy processing;

[0065]FIG. 34 is a flowchart of extraction processing;

[0066]FIG. 35 is a flowchart of the processing of modified document;

[0067]FIG. 36 is a flowchart of secret management processing;

[0068]FIG. 37 is a flowchart of record management;

[0069]FIG. 38 is a flowchart of addition to additional data;

[0070]FIG. 39 is a block diagram of management unit;

[0071]FIG. 40 is a diagram of the situation of additional data stored inthe management unit;

[0072]FIG. 41 is a flowchart of the processing of the management unit;

[0073]FIG. 42 is a flowchart of the summation of total copies;

[0074]FIG. 43 is a diagram of the result of the summation displayed inthe operational section or printed by the output section;

[0075]FIG. 44 is a flowchart of examination of flow path; and

[0076]FIG. 45 is a diagram of an example of the result of theexamination of flow path.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0077] Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the views, embodimentsof the present invention will be explained below in the following order:

[0078] (1) General outline of copy management system

[0079] (2) Binarization and embedding of additional data

[0080] (3) Detailed explanation of image processor

[0081] 3-1 Outline of the blocks in the image processor

[0082] 3-2 Image reader

[0083] 3-3 Operation unit

[0084] 3-4 Packet analysis section

[0085] 3-5 Floppy disk analysis section

[0086] 3-6 Image decision and recovery section

[0087] 3-7 Drawing section

[0088] 3-8 Additional data management section

[0089] 3-9 Secret management section

[0090] 3-10 Communication management section

[0091] 3-11 Main controller

[0092] (4) Management unit

[0093] 4-1 Structure of the management unit

[0094] 4-2 Format of memory

[0095] 4-3 Function of the management unit

[0096] (1) General Outline of Copy Management System

[0097] When a hard copy of an image read from a document is produced, adigital additional data used to manage copies is embedded in an imagedata and the synthesized image is printed. The digital additional datahas a size so small that it cannot be recognized by an ordinary userwith naked eyes.

[0098] Additional data to be embedded in a hard copy comprise forexample following data: Is this a secret document? What generation isthis copy from an original source such as an original document? When andby whom is this copy produced? That is, the additional data comprisesdata useful for copy management. Therefore, a new hard copy can beprevented to be produced from a hard copy with embedded additional data.Further, even if the secret document is leaked illegally, the leakagepath can be confirmed and traced by reading the additional data embeddedin the hard copy brought out illegally.

[0099]FIG. 1 shows a structure of a hard copy management system whichcomprises a plurality of image processors 100, 101 (and others not shownexplicitly in FIG. 1 for simplicity) for producing copies and amanagement unit 200 for managing the copies. The image processors 100and 101 produce copies of documents and send information including thenumber of the copies to the management unit 200, and the management unit200 grasps the state of each image processor 100, 101. Sources for theimage processors 100, 102 include a computer 102 and a floppy disk (FD)104 as recording media besides a document 103.

[0100] When the image processor 100, 101 produces a hard copy accordingto image data read by or received from a source, it embeds an additionaldata on copy management in hard copies and sends the additional data viaa telephone line 105 to the management unit 200 for managing the copy.If the document 103 is an original source, the image data includes onlydata on the document image. On the other hand, if the document 103 is ahard copy produced from an original source, the hard copy includesadditional data added to images in the previous copying operation aswell as the image data of the document. The management unit 200 analyzesthe total number of illegal copies derived from original sourcesaccording to the additional data and the leakage path of the illegalcopies on the basis of the additional data received from the imageprocessor 100, 101.

[0101] Table 1 shows an example of additional data which consists ofintrinsic data according to the image data received from each source andcommon data added irrespective of source. An additional data comprisesinformation on generation, user, copying apparatus and the like.Therefore, by embedding an additional data in a hard copy, the leakagepath of copies can be grasped. TABLE 1 Additional data source intrinsicdata common data document document name (e.g. book user name name) datebook code copy code page number generation code generation code passwordnumber copy code apparatus recognition code password number forgeddocument rank of secret total pixel number forged document computer dataname (file name and the like) page number floppy volume name disk filename page number

[0102] In Table 1, the book code is an intrinsic code registered foreach book in order to identify a book. The apparatus recognition code isa recognition number intrinsic for an image processor 100, 101 or thelike which can add an additional data in order to identify which imageprocessor 100, 101 processes and produces the hard copy. The volume nameis a recognition code of a floppy disk 104 in order to identify whichfloppy disk is used to produce the hard copy.

[0103] The generation code is a data used to represent the generationfrom the original source. FIG. 2 shows an example of generation codes.The generation codes of the hard copies in the first generation increasefrom “1” to “n” successively according to the sequential copy number upto “n”. The generation codes of hard copies of second generation fromthe n-th hard copy in the first generation increases from “n1” to “nm”successively according to the sequential copy number up to “m”. That is,the digits of the generation code increases with the generation. If ageneration code is not included in the image data produced from asource, a data on the generation code is added always when a copy isproduced, while if a source of the document 103 includes already ageneration code, a new modified generation code is added in hard copies.

[0104] The copy code denotes a sequential number of copies produced froma common original source, irrespective of generation code. As shown inFIG. 3, a copy code comprises an apparatus recognition code intrinsicfor an image processor, a source number intrinsic for a source and thenumber of copies. The source number is assigned sequentially if only oneimage processor is used. If a plurality of image processors is used, thesource number is assigned successively for copies for each imageprocessor or it is determined by using both copy number and apparatusrecognition code. Because the number of copies agrees with the lowestsignificant digits data in the generation code (refer FIG. 2), it can beomitted if a relation between the generation code and the number ofcopies is defined beforehand in the present system. If a copy code isincluded in an additional code as explained above, the number of thehard copies based on the same original can be obtained easily. If alegitimate user compares the copy number remembered by him or her withthe result, it can be decided if illegal copying is performed or not.

[0105] If a password is not included in the image data from the source,a user can set a password by using an operation unit provided in theimage processor 100, 101.

[0106] (2) Binarization and Embedding of Additional Data

[0107] An additional data is a digital data which can be embedded in animage as discrete points, and an example of the binary code of anadditional data is explained below. Further, the embedding of thedigital data in a plurality of areas in a hard copy will be explainednext.

[0108] An additional data is expressed as a continuous data with theabove-mentioned data lengths as shown in FIG. 4. Most of the data in anadditional data can be defined with a specific length. For example, thebook code and the book name can be expressed sufficiently with a datalength of 20 digits (20 bytes), and 20 bytes are assigned to the bookcode and the book name. Similarly, 2 bytes, 8 bytes, 4 bytes, 3 bytes, 2bytes and 1 byte are assigned to the page number, copy number, useridentification number, use time data, password number, total number ofpixels and the number of generations expressed in a generation code andgeneration code, respectively. Among the data shown in Table 1, only thegeneration code is a variable-length data and a data of 2 bytes timesthe number of generations. That is, the data length of the generationcode is increased with the number of generations so as to avoid theassignment of unnecessary data length. Then, the total length of anadditional data is 64 bytes (512 bits) or more.

[0109] Preferably, an additional data can be embedded in each hard copyin at least two positions. Further, the order of each data in theadditional data is determined beforehand, and if a relevant data is notavailable, a temporary data of “0”'s or the like is substituted in anadditional data.

[0110] The additional data has to be embedded by the image processor100, 101 in a modest way so that an ordinary man cannot recognize it.However, there may be a case wherein it is hard to embed an additionaldata in a hard copy in a modest way because the data length of theadditional data shown in FIG. 4 is long. In order to overcome thissituation, an additional data can be divided into blocks of apredetermined data length for embedding it in the unit of block in ahard copy. A block number is added to each block in order to identifythe position in the additional data. If it is difficult even to embed ablock, the order of superiority in the blocks are determined beforehand,and blocks of inferior order are omitted to be embedded. In order torecover an additional data from a hard copy, data of each block withblock number are read and the data are rearranged in the order of blocknumber to restore the additional data. The data of blocks impossible tobe read are deleted in the restored additional data.

[0111] Further, the block data may be generated in a different way. Forexample, as shown in FIG. 5, the data length of the blocks may bevariable and a code may be added at the top of the blocks in order torecognize the format. In FIG. 5, the compression code means a code datacompressed with a predetermined compression algorithm. In this method,it is needed to determine the compression algorithm of the compressioncode and the like beforehand.

[0112] In this embodiment, an additional data shown in FIG. 4 is dividedin the unit of 8 bytes. FIG. 6 shows examples of block data of the firstand 64-th blocks in this case. A block number is expressed as a 7-bitdata, and a block data of total 15 bits is defined with MSB of “11” andLSB of “01”. In order to read each block data embedded in a hard copy, adata is decided as an embedded block data if there are pixels of apredetermined number between MSB of “11” and LSB of “01”.

[0113]FIG. 7 shows a situation of embedding the block data of the firstblock shown in FIG. 6 in an image. When a block data is embedded in animage, one level (say “0”) of a binarized data is expressed at a densitywhich is the same as those of adjacent pixels, while the other level(“1”) is expressed at a density which is different a little from thoseof adjacent pixels. This data is hereinafter referred to as “densitydata”. Further, in the example shown in FIG. 7, each density data in ablock is arranged with a distance of one pixel. A block data consists oftotal 19 bits (=2+7+8+2), and it can be embedded if there is a line of alength more than 40 dots, as shown as a central horizontal dot line inFIG. 7. The 40 dots has a length of {fraction (1/10)} inch (about 2.5mm) for a printer or an image reader of a resolution of 400 dots perinch, and black lines of such a length may exist in most documentsincluding characters. That is, an additional data of 40 dots can beembedded sufficiently in such a document.

[0114] Next, the data conversion into density data and the embedding ofadditional data of blocks in an image in a hard copy is explained. FIGS.8(a)-(d) illustrates an example of the data conversion and theembedding. FIG. 8(a) denotes an enlarged view of a character “a” of afont of 12 point, while FIG. 8(b) denotes an enlarged view of a part ofthe character “a” of FIG. 8(a). In this example, an additional data(“1101”) is embedded at positions as shown in FIG. 8(c) encircled by anoval. The density data shown in FIG. 8(c) is obtained by converting thedata (“1101”) shown in FIG. 8(d), and they are embedded at a constantpitch (pixel distance).

[0115] Block data of additional data can be embedded in an image at anarbitrary position irrespective of position and direction of densitydata, and each dot of an additional data is so small not to berecognized with naked eyes. Because the embedding position of anadditional data is not definite, it becomes impossible for a user whowants to leak secret documents to copy them by shading the additionaldata embedded in a hard copy.

[0116] However, if block data are embedded in a certain area, theybecome prominent as noises. Because an additional data is desirable notto be recognized by an ordinary user, it is embedded dispersed in a hardcopy. As an example shown in FIG. 9, additional data are embedded alongthree directions, successively from a corner. Further, in order tominimize the possibility of the absence of density data for a dirtydocument or for a document prepared as a patchwork, it is desirable toembed a plurality of sets of the same additional data repeatedly in ahard copy as shown in FIG. 9. There may be a case wherein a part of anadditional data is recovered erroneously due to dirtiness or the like.In this case, an odd number of sets of additional data is embedded in ahard copy, and an effective data is determined from a decision bymajority.

[0117] For a document wherein the density of an image changedcomplicatedly, it becomes hard for an additional data to be recognizedfrom an image. Therefore, an additional data is embedded at an areawherein the density changes little. However, an additional data can alsobe embedded over a plurality of areas if there is no density change ineach of the areas for example in two areas as shown in FIG. 10(b), or ifthere are areas not having a density assigned for the additional data.

[0118] In principle, a predetermined density band is assigned fordensity data generated from block data in order to embed an additionaldata. However, as shown in FIG. 11(a), for a half-tone image wherein thedensity changes continuously, the density values are changed for adensity band “Wa” assigned to density data of block data, as shownenlarged in FIG. 11(b). That is, in FIG. 11(b), the density bands “Wb”at both sides of the density band “Wa”, the slope “1” of reproduceddensity with the image density is changed as slopes “2”, or the imagedensity of document in the density band “Wa” is driven out from the band“Wa”.

[0119] A long continuous density data cannot be embedded in some figuressuch as a pattern of parallel narrow lines or the like. In FIG. 12(a),density data can be embedded even in such a case by using each patternitself as a density data to express an additional data. Further, asshown in FIG. 12(b), a standard pattern may be embedded in parallel tothe additional data (four dots in this example) without using densitydata for MSB and LSB, and an additional data as long as the standardpattern can be embedded. In this method, though the width is enlarged,the length can be shortened.

[0120] By performing the above-mentioned procedure, an additional datais embedded in a document image (refer to step S742 in FIG. 33), and ahard copy embedded with the additional data can be printed. Then, byreading the additional data embedded in a hard copy, it can be decidedif the hard copy is related to a secret document or when was thedocument copied, which apparatus was used to copy the document, how muchwas the number of copies of the document and so on. Then, the leakage ofa secret document can be traced up to the leakage source.

[0121] (3) Detailed Explanation of Image Processor

[0122] The structure and the function of the image processor 100 forreproducing a copy is explained below in detail. FIG. 13 shows a blockdiagram of the image processor 100 and the flow of main data. The flowof the control data for controlling the timing of the entire imageprocessor 100 and the like is omitted to be displayed. The thick solidline shows a flow for image data, the thin solid line shows a flow forthe data on operation, and the dashed line shows a flow for additionaldata.

[0123] 3-1 Outline of the Blocks in the Image Processor

[0124] An outline of the blocks shown in FIG. 13 will be explainedbelow. Details of each block are explained later. An external interface1 receives image data from a computer and sends it to a packet (P)analysis section 11. The packet analysis section 11 analyzes image datareceived by the external interface 1 and extracts image data andadditional data. A floppy disk drive (FDD) 2 sends image data of afloppy disk to a floppy disk (F) analysis section 12, and the floppydisk analysis section 12 analyzes the received data to extract imagedata and additional data. A drawing section 14 generates image data incorrespondence to the image data extracted by the packet analysissection 11 or by the floppy disk analysis section 12. An image reader 3reads a document placed on a platen and sends the read data to an imagedecision recovery section 13 if the document is an original one while toan additional data management section 18 for a document including anadditional data. The image decision recovery section 13 analyzes thedata read by the image reader 3, extracts an additional data from theimage data, recovers the additional data and image data including onlyimage information. The additional data management section 18 compilesvarious additional data added to the data obtained from various sources,generates and embeds a new additional data to the image data stored inan image memory 16, and sends the additional data via a communicationmanagement section 4 to the management unit 200. The image memory 16 isused to edit image data to be printed by an output unit 6. A filing unit8 stores image information received from the image memory 16 and theadditional data from an additional data management unit 18 separately byrelating the two kinds of data. An operation unit 4 is used to setcopying conditions, to display additional data from each source, todisplay an alarm message for a copying of a secret document according toa secret management section 20 and to input a user ID number, a type ofsource and the like. The output unit 6 is an electrophotographic printerwhich produces a hard copy on the basis of image data with an additionaldata from the image memory 16 according to the instructions from theoperation unit 4. This is, a laser beam exposes a charged photoconductoraccording to the image data, and the resultant latent image is developedto be transferred on a paper with a known electrophotographic process.An editor 17 processes forging of an image in the image memory 16according to the instructions from the operation unit 4. The secretmanagement section 20 decides the inhibition of copying and the likeaccording to the additional data compiled in the additional datamanagement section 18 and to the data set by the operation unit 4. Thecommunication management section 5 sends data on the production of ahard copy via a telephone line 105 to the management unit 200 when imagedata is read from a source or when a hard copy is produced. A maincontroller 7 controls the whole sequence of the image processor 100 suchas the read of image data from a source, the start of the packetanalysis section 11 and the like, the hard copy processing, the secretmanagement and the like.

[0125] 3-2 Image Reader

[0126] The image reader 3 reads a document 103 placed on a platen and itsends the read data to the image decision recovery section 103 if thedocument is an original document while it sends an additional data aswell as image data to the image decision recovery section 103 if thedocument includes an additional data. Further, if a document isinstalled with a code transmitter, the image reader 3 receives the codeinformation and sends it to the additional data management section 18 aswill be explained later. Such a document may be a book which isinstalled with a code transmitter in order to prevent copying against acopy right.

[0127]FIG. 14 shows a block diagram of the image reader 3. In the imagereader 3, an image read section 302 reads a document set on a platen tosend the image data to an image reader controller 301, which sends theimage data via an image interface 304 to a bus B7. A code data readsection 303 reads code data other than the image data to send it to theimage reader controller 301, which sends the code data via a codeinterface 305 to a bus B11. An automatic document feeder 307 dischargesa document on the platen and feeds a new document on the platenautomatically. The image reader controller 301 controls variouscomponents such as a motor to drive the image reader 3.

[0128]FIG. 15 shows an apparatus which plays roles as the image readsection 302 and the code read section 303. A document is placed on aplaten glass 3021. A code data is read wireless with use ofelectromagnetic waves. That is, a code transmitter 3030 installed in adocument such as a book transmits code data such as a book name, bookcode and the like, and the code data is detected with an antenna coil3031. Because wireless data is received, a read error due to dirtinessof the platen glass 3021 can be prevented. A sender/transmitter 3032receives the code data and sends it via a code converter 3033 to theimage reader controller 301 (FIG. 14).

[0129] This type of code reader 303 cannot be used for documents such asa sheet of paper which cannot contain a code transmitter 3030. Theantenna coil 3031 is made of a transparent material on the platen glass3020. However, a coil 3031′ may be provided on a scanner 3022 whichmoves below the platen 3021 to scan a document on the platen glass 3021.The document is exposed by a lamp 3023.

[0130] When the antenna 3031 is used, the code data is read before thescan of the scanner 3022 for image read and before the turning on of theexposure lamp 3023 in order to avoid read errors due to noises generatedby the image reader 3 itself. When the coil 3031′ is used, the code datais read in a prescan before turning on the exposure lamp 3023 in orderto reduce noises as much as possible.

[0131]FIG. 16 shows a flow of the image reader controller 301. When anelectric power source of the image reader 3 is turned on, theinitialization is performed first (step S301). For example, the scanner3022 is positioned at the start position and the output of the exposurelamp 3023 is kept constant. Next, if a user has decided to press a codedata read key (not shown) provided in the operation unit 4 (YES at stepS302), code data (additional data) of a document on the platen glass3021 is read (step S303). When a code transmitter 3030 is installed in adocument, the code data is received by the antenna 3031 or by the coil3031′. Then, the code data is sent to the image reader controller 301via the sender/transmitter 3032 and the code converter 3033 (step S304).Next, if an image read key (not shown) provided in the operation unit 4is decided to be pressed (YES at step S305), the image read section 302reads a document on the platen 3021 (step S306). That is, in the imageread section 302, a document is exposed by the lamp 3023, the scanner3022 is moved to read image data, and the obtained image data are sentto the image reader controller 301.

[0132] 3-3 Operation Unit

[0133]FIG. 17 shows a block diagram of the operation unit 4 shown inFIG. 13. In the operation unit 4, copying conditions are set, additionaldata read from each source are displayed, a password, a user ID, thesource type or the like can be inputted, and an alarm is displayed whenthe secret management unit 20 decides to prohibit the copying.

[0134] An operation controller 401 controls the operation unit 4. Amessage display 402 displays an additional data read from a source, anddisplays an alarm message when the secret management section 20 decidesto prohibit the copying. A setting input section 403 is used todesignate the type of source, to set the copying conditions of theoutput unit 6 for producing a hard copy, to indicate the forgingprocessing for the editor 17 and to input a user ID number and the like.An IC card interface 404 is used to input a user ID number with use ofan IC card owned by each user. The input data is sent via an interface405 to a bus B3 to the external. A calendar 406 manages the year, month,day and time. An intrinsic data memory 407 stores intrinsic recognitioncode which has been determined beforehand for each image processor.

[0135] 3-4 Packet Analysis Section

[0136] The packet analysis section 11 shown in FIG. 13 analyzes theimage data received from the computer 102 via the external interface 1.FIG. 18 shows a block diagram of the packet analysis section 11. Imagedata is received via an interface 112 and stored in a buffer 113. Theimage data received by the interface 112 has a predetermined format andas shown in FIG. 19, it consists of an image data and an additionaldata. The additional data includes a data name such as a file name and apage number, while the image data includes a format designation data, aposition designation data, character codes and figure codes. The packetanalyses processor 111 analyzes the image data stored in the buffer 113by using a work memory 114 and sends image data on print output via aninterface 116 to the drawing section 14 and an additional data via aninterface 117 to the additional data management section 18. The drawingsection 14 generates image data in an image memory 18 according to thereceive image data.

[0137]FIG. 20 shows a flow of the analysis of the packet analysis unit11. This processing may be performed by the packet analysis controller111. After the initialization (step S1101), an image data is waited tobe received from the external interface 1 connected to the computer 102(step S1102). When an image data is received, the data is analyzed. Thatis, print data (character codes and figure codes) (YES at step S1103)are sent to the drawing section 14 (step S1104). If a format controldata such as a format data or a print position data is received (YES atstep S1105), internal edition conditions are changed according the data(step S1106). If an additional data is received (YES at step S1107), itis sent to the additional data management section 18 (step S1108).Otherwise a different processing is performed (step S1109). Thisprocessing may also be performed by a processor 701 in the maincontroller 7 with time sharing.

[0138] 3-5 Floppy Disk Analysis Section

[0139]FIG. 21 shows a block diagram of the floppy disk analysis section12 which analyzes the image data stored in a floppy disk. A floppy diskstores a plurality of files, and a file is designated via a bus B9 fromthe operation unit 4. Image data in a floppy disk is received via aninterface 122 and stored in a buffer 123. The image data received by theinterface 122 has a predetermined format and as shown in FIG. 22, itconsists of an image data and an additional data. The additional dataincludes a volume name of the floppy disk, a data name such as a filename and a page number, while the image data includes a formatdesignation data, a position designation data, character codes andfigure codes. The floppy disk analysis processor 121 analyzes the imagedata stored in the buffer 123 by using a work memory 124 and it sendsimage data on print output via an interface 126 to the drawing section14 and an additional data via an interface 127 to the additional datamanagement unit 18. The drawing section 14 generates image data in animage memory 18 according to the receive image data.

[0140]FIG. 23 shows a flow of the analysis of the floppy disk analysisunit 21. This processing may be performed by the floppy disk analysiscontroller 121. After the initialization (step S1201), an image data iswaited to be received via a bus B6 connected to the floppy disk drive 2(step S1202). When an image data is received, the data is analyzed. Thatis, print data (character codes and figure codes) (YES at step S1203)are sent to the drawing section 14 (step S1204). If a format controldata such as a format data or a print position data is received (YES atstep S1205), internal edition conditions are changed according to thedata (step S1206). If an additional data is received (YES at stepS1207), it is sent to the additional data management section 18 (stepS1208). Otherwise a different processing is performed (step S1209). Thisprocessing may also be performed by a processor 701 in the maincontroller 7 with time sharing.

[0141] 3-6 Image Decision and Recovery Section

[0142] The image decision and recovery section 13 analyzes image data toseparate image data on printing from block data embedded as anadditional data. Further, it recovers a continuous additional data fromthe block data, and it also recovers the image data of a document beforeadding the additional data.

[0143]FIG. 24 shows a block diagram of the image decision recoverysection 13. Image data is received via an interface 132 and stored in animage memory 133. The image analyzes processor 131 analyses the imagedata stored in the image memory 133 by using a characteristic pointmemory 134 and a block management memory 135 and sends recovered imagedata via an interface 136 to the drawing section 14 and an additionaldata via an interface 137 to the additional data management unit 18.

[0144]FIG. 25 shows a flow performed by an image analysis processor 131.After the initialization (step S1301), an image data is received (YES atstep S1302). Then, the image data are divided into areas each fordifferent density distribution in an image (step S1303), and coordinatesfor characteristic points are searched (step S1304). A characteristicpoint denotes a pixel having a predetermined density (refer FIG. 7).Further, binary numbers are extracted from the characteristic pointsaccording to the predetermined position relation (step S1305, refer toFIG. 26). The binary numbers extracted in the unit of blocks arerearranged in the order of block number according to a predeterminedprocedure to recover an additional data (step S1306, refer to FIG. 27).After the extraction of binary numbers is completed, the characteristicpoints are deleted from the image data (step S1307) to recover an imagedata before adding the additional data. The deletion of characteristicpoints can be performed by replacing each characteristic point with adensity of the pixels adjacent to the characteristic point. Theextracted additional data is sent via the interface 137 to the bus B11(step S1308), while the recovered image data is sent via the interface136 to the bus B4 (step S1309). Then, the flow returns to step S1302.

[0145]FIG. 26 shows a flow of the extraction of binary number (stepS1305 in FIG. 25). The extraction of binary numbers from characteristicpoints is performed by judging the position relation of characteristicpoints. In this embodiment, a block of an additional data is embeddedlinearly within a predetermined range. The embedding may not necessarilybe performed in a linear line and may be performed for example on an arcif the position relation is defined beforehand.

[0146] First, a characteristic point is designated (step S1310). Then,all the other characteristic points existing within the predeterminedrange are searched (step S1311). The maximum length of the predeterminedrange amounts to the length of a block (i.e. the bit length times thebit-to-bit distance). Next, it is confirmed if the coordinates of thecharacteristic points have the predetermined position relation (a linearline in this example) (step S1312), and invalid coordinates and data aredeleted (step S1313). Then, the coordinates of the valid data of a blockare converted to a binary number (step S1314). Next, if it is decidedthat the binary number has a prescribed number of bits (YES at stepS1315) and that the binary number includes top and last recognition bits(YES at step S1316), the binary data is stored as a valid data (stepS1317). The above-mentioned processing is repeated until allcharacteristic points are processed (YES at step S1318).

[0147]FIG. 27 shows a flow of the recovery of additional data (stepS1306 in FIG. 25) wherein the data of the valid blocks obtained at stepS1305 are converted to a binary data. First, the data of the validblocks are arranged in a row in the order of block number included inthe data (step S1320). Then if it is decided that blocks enough at leastto recover an additional data are available (YES at S1323), the data ofeach block is checked (step S1322). In this embodiment, a plurality ofsets of an additional data is embedded in a hard copy, and it isverified if the data of the same block number are the same with eachother. If the data of the same block number are not the same, the dataof the majority is adopted. If the data of the blocks cannot bedetermined by the majority decision, the data is made invalid. If thenumber of invalid blocks is more than a predetermined number (YES atstep S1323), this means that the hard copy is a forged document madefrom a patchwork of a plurality of documents, and the flow returnsreadily to the main flow to report it to the additional data managementsection 18. If it is decided that the hard copy is not a forged document(NO at step S1323), the data of the invalid blocks are deleted (stepS1324) and the data of the valid blocks are rearranged to recover anadditional data (step S1325). Further, imperfect data having defects areinitialized with predetermined values such as zeros or spaces(stepS1326). The additional data recovered in this way are used by the maincontroller 7, the additional data management section 18 and themanagement unit 200, as will be explained later.

[0148] 3-7 Drawing Section

[0149] As shown in FIG. 13, the drawing section 4 draws an image in theimage memory 16 according to the character codes and figure codesreceived via the bus B3 from the packet analysis section 11 or thefloppy disk analysis section 12. The structure and the drawing techniqueare similar to those for a bit map type printer controller. However, ifthe image to be drawn is a half-tone image, density bands assigned forblock data are not used (refer FIG. 7).

[0150] 3-8 Additional Data Management Section

[0151] The additional data management section 18 shown in FIG. 13receives additional data via the bus B11 from the packet analysissection 11, the floppy disk analysis section 12, the image decisionrecovery section 13 and the operation unit 4, and compiles and managesthe receive data for each source. As will be explained later, thecompiled additional data is used to generate an additional data newly ina hard copy processing (refer to step S739 in FIG. 33) carried out bythe main controller 7, and the generated additional data is embedded ina hard copy (refer to steps S742 and D743 in FIG. 33).

[0152]FIG. 28 shows a structure of the additional data managementsection 18. A processor (CPU) 181 receives code data from the bus B11through a code interface 182 and operation data via an operation datainterface 184, and it makes a drawing section 183 embed an additionaldata in an image stored in the image memory 16 (FIG. 13). The processor181 is controlled by the main controller 7. The processor 181 accessesdirectly the image memory 16 via the bus B1 when additional data ofblocks designated by the operation unit 4 are searched by using an areanot used in the image memory 16 as a work area. A counter 186 counts thearea of a pattern by counting the number of pixels. An image comprisesdensity data of a prescribed resolution, and the area is obtained forsimplicity by counting the number of pixels having a density larger thana prescribed density. In order to improve the precision of themanagement, the areas of various density bands may be counted. TABLE 2Data received from various sources intrinsic sender source informationimage reader book document name (e.g. book name) book code imagedocument document name (e.g. book name) decision book book code recoverypage number section generation code copy code password number rank ofsecret total pixel number forged document code packet computer data name(e.g. file name) analysis page number section floppy disk files ofvolume name analysis floppy disk file name section page number operationvalues set user name (user code) unit by a user date IC card number ofcopies password number apparatus recognition code

[0153] Table 2 shows a part of additional data sent from various sourcesto the additional management section 18. The value of the rank of secretis increased with increasing degree of secret (for example 5 for thehighest secrets). If the value is zero, it means an ordinary documentwhich is not needed to be secret.

[0154] The additional data received by the additional data managementsection 18 are classified for each source as shown in Table 3. Usually,only one set of data on the source is embedded in a hard copy. However,a forged document made of a patch work of a plurality of documents mayinclude a plurality of sets of data. In such a case, the additional datamanagement section 18 manages the plurality of sets of data, while thesame values are used for the data other than the source data. TABLE 3Classification of additional data Additional source data name (e.g.document name, data file name, data name) book code page numbergeneration code * rank of secret password number forged document codetotal pixel number * copy code * copy conditions number of copies userdata user name apparatus data date apparatus recognition code

[0155] Next, it is explained how to generate a new additional data(refer step S739 in FIG. 33). A document name can be added by a userwith the operation unit 4 or generated from the date and the user name,while a book code are stored in a code transmitter 3030 installed onforming a document. The data is fixed. The same data is transferred oncopying.

[0156] A page number, a file name, a volume name and a data name aresent at the same time as the print data on printing from a wordprocessor or a computer. The data is fixed. The volume name is receivedfrom the computer 102, while the data name is received from a floppydisk 104.

[0157] A generation code is added by the main controller 7 automaticallyon printing a hard copy. When a hard copy is produced newly, thegeneration is set to be one and the generation code is expressed as “1n”wherein the first digit “1” means the generation number and the lastdigit “n” means the sequential number of copies obtained from the samesource. The generation number of a hard copy without an additional datais also set to be one. The generation code is increased for each copyingof a new generation (refer FIG. 2.).

[0158] A copy code is generated successively in an image processor. Itis not related to the additional data included in a document.

[0159] A password and a rank of secret are kept the same if included ina document. They are set by the operation unit 4 if not included in adocument. A password once set cannot be changed.

[0160] A total pixel number is counted when the edition of an outputimage is completed. The pixels for the additional data included in adocument are not counted.

[0161] A date when a hard copy is produced is set by using a calendarprovided in the operation unit 4.

[0162] A user name and a user ID number are read from an IC card whichis set by a user in the operation unit 4.

[0163] An apparatus recognition code is intrinsic for a printer and itis registered beforehand in the additional data management section 18. Ahard copy produced with the same printer has the same apparatusrecognition code.

[0164] A forged document code is kept the same if included in adocument. It is added newly when it is decided to be a forged documentby the main controller 7.

[0165] As explained above, each data included in an additional data canbe generated and can be embedded in a hard copy. Therefore, by analyzingan additional data in a hard copy, a user name, a date, the number ofcopies can be obtained for each hard copy, and the analysis of theleakage path of a secret document becomes easy.

[0166]FIG. 29 shows a flow of embedding an additional data (step S742 inFIG. 33) carried out by the additional management section 18 under thecontrol of the main controller 7. First, block data of binary number aregenerated by dividing an additional data into blocks of a predetermineddot number added with a block number (step S1801, refer FIG. 30). Next,in order to embed each block data in a hard copy as shown in FIGS. 7 and8, the values of the block data are converted into signals of densitydata (step S1802). Then, areas for embedding the block data in a hardcopy are searched (step S1803). Then, if an area as long as apredetermined length is decided to exist (YES at step S1804) or if anarea is decided not so long as the predetermined length but it isdecided to be extensible to an adjacent area because the density changesgradually (YES at step S1805), the positions of each dots are determined(step S1806), and the density values in a density block appropriate forthe positions are determined for the positions (step S1807). Next, theblock data determined above are written in the image data (step S1808).The above-mentioned processing is repeated until all additional data areprocessed (YES at step S1809). Further, the above-mentioned processingis repeated until a predetermined number of sets are embedded (YES atstep S1810).

[0167]FIG. 30 shows a flow of the generation of data to be embedded(step S1801 in FIG. 29). First, check codes for making it possible torecover embedded block data and codes for error correction arecalculated (step S1820), and the total data length of an additional dataillustrated in FIG. 4 is calculated (step S1821). Further, the bitnumber for dividing the additional data into blocks is calculated andthe number of blocks is calculated (step S1822). Further, a block numberis added to each block data obtained by dividing the additional data(step S1823) and the mark LSB for designating the start of the blockdata and the mark MSB for designating the end of the block data areadded (steps S1824 and S1825). Thus, a block data as shown in FIG. 6 canbe generated.

[0168] 3-9 Secret Management Section

[0169] When the additional data management section 18 detects a secretdocument having a rank of one or more, the secret management section 20requests the operation unit 4 to input a password or if a book code isset in the additional data, a book code. If a password and a book codeif necessary are received from the operation unit 4, the secretmanagement section 20 compares them with the counter-parts managed bythe additional data management section 18, and sends the result to theoperation unit 4. If the password and the book code received from theoperation unit 4 are different from the counterparts in the additionaldata management section 18, the secret management section 20 prohibitsthe copying to prevent the illegal leakage of a secret document. Theabove-mentioned processing is carried out by the main controller 7(refer to step S715 in FIG. 32).

[0170] 3-10 Communication Management Section

[0171] The communication management section 5 transmits additional datacompiled and managed by the additional data management section 18 via atelephone line to the management unit 200 each time an image data isreceived from a source or a hard copy is produced.

[0172] 3-11 Main Controller

[0173]FIG. 31 shows a structure of the main controller 7 which carriesout the read of image data from each source, the start of the packetanalysis section 11, the floppy disk analysis section 12 and the imagereader 3, and the sequence control of the hard copy processing and thesecret management. The main controller 7 consists of a processor (CPU)701, a program memory 702 storing a program run by the processor 701, adata memory 703, and an interface 704 with each function block in theimage processor 100.

[0174]FIG. 32 shows a flow of the processor 701. First, the maincontroller 7 is initialized (step S701) and the initialization of theimage processor 100 is commanded (step S702). The processing is startedwhen a user inputs a request with the operation unit 4 (YES at stepS703) or when the computer 102 sends a data (YES at step S704).

[0175] If the input from the computer 102 is an analysis request for thepacket analysis section 11 (YES at step S704), it is waited that thecompletion of the processing is received from the packet analysissection 11. The packet analysis section 11 analyzes a page of data asexplained above, and separates the additional data from the image data.Then, the packet analysis section 11 sends the image data to the drawingsection 14 to draw an image in the image memory 16 while it sends theextracted additional data to the additional data management section 18.Finally, the packet analysis section 11 sends the completion of theprocessing to the main controller 7. Then, the main controller 7 makesthe additional data management section 18 transmit the additional datato the management unit 200 (step S705), and it makes the output unit 6print the image in the image memory 16 to output a hard copy (step S706,refer to FIG. 33). This processing is performed for each page of thedata from the computer 102. Then, the flow returns to step S703.

[0176] If a print start is decided to be instructed with the operationunit 4 (YES at step S707), it is decided next if a floppy disk is set inthe floppy disk drive 2 (step S708). If a floppy disk is decided to beset, a hard copy of a file stored in the floppy disk is requested to beproduced so that the floppy disk analysis section 12 is activated (stepS709). As explained above, the floppy disk analysis section 12 separatesthe additional data from the image data. Then, the floppy disk analysissection 12 sends the image data to the drawing section 14 to draw animage in the image memory 16 while it sends the extracted additionaldata to the additional data management section 18. Finally, the floppydisk analysis section 11 sends the completion of the processing to themain controller 7. After the completion of the processing of the floppydisk analysis section 12, the main controller 7 makes the additionaldata management section 18 transmit the additional data to themanagement unit 200 (step S710), and it makes the output unit 6 printthe image in the image memory 16 to output a hard copy (step S711, referto FIG. 33). A file in the floppy disk consists of a plurality of pagesand this processing is performed in the unit of a page. If theprocessing of all pages is decided to be completed (YES at step S712),the flow returns to step S703.

[0177] If a floppy disk is decided not to be set, the image reader 3 isactivated (step S713). Then, as explained above, the image reader 3reads a document on the platen glass and reads a book code if thedocument is a book with a code transmitter. Then, the image decisionrecovery section 13 is activated (step S714). Then, as explained above,the image decision recovery section 13 checks the block data of anadditional data embedded in a hard copy and recovers the additionaldata. Then, the image decision recovery section 13 sends the additionaldata to the additional data management section 18 and stores therecovered image data in the image memory 16. After the completion of theprocessing of the image decision recovery section 13, the maincontroller 7 performs the secrecy management (step S715, refer to FIG.36). If the document is decided not to be a secret document or ifprescribed data including a password is inputted for a secret document(YES at step S716), the book code received by the additional datamanagement section 18 and the additional data recovered by the imagedecision recovery section 13 are sent via the communication managementunit 5 to the control unit 200 (step S717), and a hard copy is producedby sending the image data from the image memory 16 to the output unit 6(step S718, refer FIG. 33). If a plurality of documents is set in theautomatic document feeder 307, the above-mentioned processing isrepeated until all pages are printed (YES at step S719). Then, the flowreturns to step S703.

[0178] When a mode is set with the operation unit 4 (step S720), if asecrecy mode is decided to be set (YES at step S721), the mode ischanged to the secrecy mode (step S722). If record management isinstructed for managing the generation of hard copy and the sum of copynumber (YES at step S723), a password is received (step S724), and ifthe password received is verified to agree with the registered password(YES at step S725), the record is verified next (S726, refer to FIG.37). If the record management is decided not to be instructed for themanagement (NO at step S723), a data is added to the additional data tobe embedded in a hard copy (step S727, refer to FIG. 38). Then, the flowreturns to step S703.

[0179]FIG. 33 shows a flow of hard copy processing (steps S706, S711,S718 in FIG. 32). First, the area of a pattern of image drawn in theimage memory 16 is measured (step S730). Though an image consists ofdensity data of a predetermined resolution, the total number of pixelshaving a density larger than a predetermined value is counted as thearea of a pattern for simplicity. Next, the extraction processing isperformed for secret management (step S731, refer to FIG. 34).

[0180] Then, it is decided if the document is a forged document (stepS732). In this decision, the total number of pixels set in theadditional data is compared with that counted at step S730, and if thedifference between them is larger than a predetermined number, thedocument is decided to be a forged document. Further, if the imagedecision recovery section 13 decides that the document is a forgeddocument because a plurality of additional data is included, thedocument is decided to be a forged document. If the document is decidedto be a forged document (YES at step S732), forging record processing isperformed (step S733, refer to FIG. 35).

[0181] Next, the additional data is instructed to be displayed by theoperation unit 4 (step S734). However, the password and the like are notdisplayed because they are secrets.

[0182] Then, the editor 17 is requested to edit the document image ifthe edition is instructed with the instruction unit 4 (step S735). Ifthe document image is decided to be changed according to the edition(YES at step S736), it is decided that a part of the document is forgedand the forging record processing is performed (step S737, refer to FIG.35). Thus, the above-mentioned processing on forging is completed, andthe master data are saved in the image memory 16 (step S738).

[0183] Next, a hard copy is produced. That is, the main controller 7generates a new additional data by sending a command to the additionaldata management unit 18 (step S739), and sends the additional data tothe management unit 200 (step S740). Then, the data saved in the imagememory 16 is read again (step S741), and the additional data is embeddedin the image data by the additional data management section 18 (stepS742, refer to FIGS. 29 and 30), as explained above in detail. Next, theoutput unit 743 is activated (step S743). Thus, the image data is readfrom the image memory 16 synchronously with the output unit 6 forprinting. After the completion of the hard copy (YES at step S744), ifit is decided that hard copies of the predetermined total number is notcompleted (NO at step S745), the flow returns to step S739. Thegeneration code and the copy code are updated for each hard copy.Further, as to the total number of pixels, the count on the image afterthe edition (step S735) is added.

[0184]FIG. 34 shows a flow of the extraction processing (step S731 inFIG. 33) for monitoring what is copied for each user. First, a user nameis confirmed at the setting of an IC card and the like by the additionaldata management section 18 (step S770), and the additional data (storedin the additional management section 18) on the source to be printed iscompared with the previous history of the user on the hard copiesreproduced by the user stored in the filing unit 8 (step S771). If it isdecided that the source under printing is determined to be a new sourcefor the user (YES at step S772), the additional data and the image dataare stored in the filing unit 8 (steps S773 and S774).

[0185]FIG. 35 shows a flow of forging record processing (steps S733,S737 and S757 in FIG. 32). The image data decided to be a forgeddocument is read (step S780), and the additional data and the image dataare filed in the filing unit 8 (step S781 and S782).

[0186]FIG. 36 shows a flow of secrecy management processing (step S715in FIG. 32). The main controller 7 activates the secret managementsection 20 to check the rank of secret (secrecy rank) included in theadditional data of the source read by the additional data managementunit 18. If the rank is decided to be one or more (YES at step S750), aconfirmation data is requested to be received. That is, if a book codeis decided to be set in the additional data (YES at step S751), a bookcode is received from the operation unit 4 (step S752). If a password isdecided to be set in the additional data (YES at step S753), a passwordis received from the operation unit 4 (step S754). Then, the input bookcode or password is decided not to agree with the data set in theadditional data (NO at step S755), an alarm message is displayed in theoperation unit 6 (step S756), and the forging record processing isperformed (step S757, refer to FIG. 35). Thus, the illegal copy of asecret document can be prevented effectively. On the other hand, for adocument of the rank of secret of zero, a password or the like is notrequested to be inputted, and the copying operation of an ordinarydocument is not interfered.

[0187]FIG. 37 shows a flow of the record verification processing (stepS726 in FIG. 32) for verifying the history of a hard copy from theadditional data such as the generation code or the copy code stored inthe filing unit 8. An item in a record includes user names and thecorresponding images filed in the filing unit 8 (step S731 in FIG. 34).When a user sets search items (step S760), additional data are searched(step S761). If there is decided to be a corresponding data (YES at stepS762), the searched additional data is displayed in the operation unit 4(step S763). Further, if a print is decided to be requested (YES at stepS764), the additional data and the image data are stored in the imagememory 16 (step S765), and the output unit 6 is activated to print thedata (step S766). After the hard copy is decided to be completed (YES atstep S767), if it is decided that the search of all items set at stepS760 is not completed (NO at step S768), the flow returns to step S761.Thus, the analysis of leakage path becomes easy by using the additionaldata. Further, because forged or edited documents can also be examined,it is not needed to check a document itself to determine if the forgingor edition is performed or not.

[0188]FIG. 38 shows a flow of the addition of additional data (step S727in FIG. 32). When a data to be added is received (step S790), if it isdecided to be a new password (YES at steps S791 and S792), the passwordis set in the additional data and it is stored in the additional datamanagement section 18 (step S793). If the data is decided to be the rankof secret which is newly set (YES at steps S794 and S795), the data isadded to the additional data and it is stored in the additional datamanagement section 18 (step S796). Otherwise a different processing isperformed (step S797).

[0189] (4) Management Unit

[0190] 4-1 Structure of the Management Unit

[0191]FIG. 39 shows a block diagram of the management unit 200 whichcomprises a processor (CPU) 204 for controlling the management unit 200.A terminal 201 is used to operate the management unit 200 and to displayvarious data and messages. A communication section 203 communicates viathe telephone line 105 with the image processors 100, 101 to receive andsend an additional data or the like. Usually a plurality of imageprocessors 100, 101 are connected to the management unit 200. The datareceived by the communication unit 203 are the data on all hard copiesprocessed by the image processors. All additional data received arestored in a memory 205 and the result of copy management can be printedwith a printer 202. For example, the management unit 200 counts thetotal copy number of a specified document, confirms the leakage path ofa specified document and searches a document of the rank of secret ofone or more.

[0192] 4-2 Format of Memory

[0193] The additional data received by the management unit 200 arestored in the memory 205 and managed systematically. First, anadditional data is classified for each image processor, and eachadditional data for an image processor is stored as a record. Eachrecord comprises an additional data embedded in a source and anadditional data to be embedded in a hard copy. As compiled in Table 1,the additional data embedded in a source includes, for example, adocument name, book code, page number, generation code, copy code,password number, rank of secret, total pixel number and forged documentcode.

[0194] 4-3 Function of the Management Unit

[0195]FIG. 41 shows a flow of the management unit 200. If an additionaldata is decided to be received from the additional data managementsection 18 or the secret management section 20 (YES at step S5001), theadditional data is stored in the memory 205 (step S5002). If the totalcopy number including generation copy is decided to be instructed withthe terminal 201 (YES at step S5003), the total copy number is counted(step S5004, refer FIG. 42). That is, the copy number of a specifiedsource can be determined from the records and it can be decided if thesecret copy is leaked illegally or not by comparing it with the totalnumber of hard copies recorded separately. If the confirmation ofleakage path is decided to be instructed with the terminal 201 (YES atstep S5005), the leakage path is confirmed (step S5006, refer FIG. 44).Otherwise if for example the detection of the hard copy of secretdocuments is instructed, the records for documents of the rank of secretof one or more are searched and the result is displayed at the operationunit 4 or printed at the output unit 6. Therefore, the situation of thecopying of secret documents can be checked. If necessary, the name ofsource, a user name and the like can be detected.

[0196]FIG. 42 shows a flow of the summation of total copy number (stepS5004 in FIG. 41). First, a source to be summed is designated with theterminal 201 (step S5010). Usually, a document name, a book code or apage number is inputted. Then, all records on the specified source aresearched in the memory 205 (step S5011). Next, the generation of therecords is analyzed and a tree map of copy numbers in each generation isproduced (step S5012). Usually, a tree map corresponds with thegeneration code. However, if there is a plurality of sources of the samedocument name, copy code is used instead of generation code. Next, thecopy number is summed (step S5013). If there is a plurality of treemaps, the sum is obtained for each tree map. Then, the results aredisplayed at the terminal 201 and are printed if necessary (step S5014).

[0197]FIG. 43 shows an example of a tree map obtained at step S5004. Thehard copies obtained from the same original document are classified. Ateach generation, the apparatus recognition code and a user name areshown with a sum of the number of hard copies as well as the total sumthereof.

[0198]FIG. 44 shows a flow of the confirmation of leakage path (stepS5006 in FIG. 42). First, a source to be summed is designated with theterminal 201 (step S5020). Usually, a document name, a book code or apage number is inputted. Then, all records on the specified source aresearched in the memory 205 (step S5021). Next, the generation of therecords is analyzed and a tree map of the records at each generation isproduced (step S5022). Usually, a tree map is generated with respect tothe generation code. However, if there is a plurality of sources of thesame document name, the copy code is used instead of the generationcode. Next, the obtained tree map is displayed at the terminal 201 andis printed if necessary (step S5023).

[0199]FIG. 45 shows an example of a tree map obtained at step S5006. Thehard copies obtained from the same original document are classified. Ateach generation, the apparatus recognition code and a user name areshown.

[0200] Although the present invention has been fully described inconnection with the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

What is claimed is:
 1. An image forming apparatus comprising: a memorymeans for storing image data of a hard copy of a document; an embeddingmeans for embedding an additional data into the image data stored insaid memory means, which additional data comprising data on themanagement of copy, which additional data comprising discrete dotsarranged in a prescribed format; and an image forming means forproducing a copy according to the image data including the additionaldata embedded by said embedding means.
 2. The image forming apparatusaccording to claim 1, further comprising a read means for reading animage of a document, wherein said memory means storing the image dataread by said read means.
 3. The image forming apparatus according toclaim 1, further comprising an analysis means for analyzing image datareceived from a computer or from a floppy disk drive so as to be storedin said memory means, wherein said memory means stores the image datareceived from said analysis means.
 4. The image forming apparatusaccording to claim 1, wherein said additional data comprises a pluralityof block data, each block data further comprising a data to identify theblock.
 5. The image forming apparatus according to claim 1, wherein saidembedding means decides the density of the discrete dots so that thedensity of the discrete dots is different from the density adjacent tothe discrete dots.
 6. The image forming apparatus according to claim 1,wherein the size of each of said discrete dots is not so large as to berecognized easily with naked eyes.
 7. The image forming apparatusaccording to claim 1, wherein said additional data comprises a data toidentify a copy to be reproduced by said image forming means.
 8. Theimage forming apparatus according to claim 7, wherein said additionaldata further comprises data to identify said image forming apparatus anda user who operates said image forming apparatus.
 9. The image formingapparatus according to claim 7, wherein said additional data comprises adata on the generation of copy with respect to the original source. 10.The image forming apparatus according to claim 7, wherein saidadditional data comprises a data to identify a sequential number ofcopies obtained from the same document.
 11. The image forming apparatusaccording to claim 7, wherein said additional data comprises a data onthe rank of secret of a document.
 12. The image forming apparatusaccording to claim 1, wherein said embedding means embeds the sameadditional data at a plurality of positions.
 13. An image formingapparatus comprising: a memory means for storing the image data of ahard copy of a document, which image data including an additional dataembedded in the inherent image in the document, which additional datacomprising discrete dots arranged in a prescribed format; and anextraction means for extracting an additional data embedded in theinherent image.
 14. The image forming apparatus according to claim 13,further comprising a read means for reading an image of a document,wherein said memory means storing the image data read by said readmeans.
 15. The image forming apparatus according to claim 13, furthercomprising an analysis means for analyzing image data received from acomputer or from a floppy disk drive so as to be stored in said memorymeans, wherein said memory means stores the image data received fromsaid analysis means.
 16. The image forming apparatus according to claim13, wherein the density of the discrete dots is different from thedensity adjacent to the discrete dots and said extraction means extractsthe additional data from the density of the image data.
 17. The imageforming apparatus according to claim 13, wherein said additional datacomprises a plurality of block data, each block data further comprisinga data to identify the block, and said extraction means reconstructs theadditional data from the data of the blocks.
 18. The image formingapparatus according to claim 13, wherein said extraction means verifiesthe additional data with the majority decision if a plurality ofadditional data is extracted.
 19. The image forming apparatus accordingto claim 13, wherein said additional data comprises the total number ofpixels included in an image and said extraction means further comprisinga count means for counting the total number of pixels included in theimage in the hard copy, which image forming apparatus further comprisinga decision means for deciding a forged document if the total numbercounted by said count means is different from that extracted by saidextraction means.
 20. The image forming apparatus according to claim 13,wherein said extraction means decides that the hard copy is an editeddocument if a plurality of additional data is extracted from the hardcopy.
 21. The image forming apparatus according to claim 13, furthercomprising a filing unit for storing image data of an image which isdecided to be new according to the additional data extracted by saidextraction means and the additional data.
 22. The image formingapparatus according to claim 13, further comprising: an image formingmeans for producing a copy according to the image data; and a controlmeans for controlling said image forming means according to theadditional data extracted by said extraction means.
 23. The imageforming apparatus according to claim 22, wherein said control meanscomprises a recovery means for recovering image data at the positionsused to express the additional data and said image forming meansproduces a copy according to the image data including the data recoveredby the recovery means.
 24. The image forming apparatus according toclaim 22, wherein said additional data comprises a data to identify adocument to be reproduced by said image forming means and a data toidentify a user of said image forming means; said apparatus furthercomprising a decision means for deciding if the reproduction of thedocument is not legitimate from the additional data extracted by saidextraction means and inhibits the reproduction of said image formingmeans if said decision means decides that the reproduction is notlegitimate.
 25. The image forming apparatus according to claim 22,further comprising a display means for displaying an alarm message whensaid decision means decides that the reproduction of the document is notlegitimate.
 26. An image forming apparatus comprising: a memory meansfor storing the image data of a hard copy of a document, which hard copybeing embedded with an additional data comprising data on the managementof copy, which additional data comprising discrete dots arranged in aprescribed format; an extraction means for extracting additional dataembedded in the document image; a generation means for generating anadditional data according to the extracted additional data; an embeddingmeans for embedding the additional data generated by said generationmeans into the image data stored in said memory means; and an imageforming means for producing a copy according to the image data stored insaid memory means.
 27. The image forming apparatus according to claim26, wherein said additional data comprises data on the generation andthe copy number and said generation means generates data on thegeneration and the copy number.
 28. The image forming apparatusaccording to claim 26, wherein said additional data comprises a data toidentify a copy to be reproduced by said image forming means.
 29. Theimage forming apparatus according to claim 26, wherein said additionaldata comprises data to identify said image forming apparatus and a userthereof.
 30. The image forming apparatus according to claim 26, whereinsaid additional data generated by said generation means comprises a dataon the generation of copy with respect to the original source.
 31. Theimage forming apparatus according to claim 26, wherein said additionaldata generated by said generation means comprises a data to identify asequential number of copies obtained from the same document.
 32. A copymanagement system comprising: at least one printer for producing a copy;and a management means for managing copies produced by said at least oneprinter; said printer comprising: a read means for reading a hard copyof a document, which hard copy including an additional data embedded inthe inherent image of the document, which additional data comprisingdiscrete dots arranged in a prescribed format; an extraction means forextracting the additional information embedded in the hard copy from theimage data obtained by said read means image; and an image forming meansfor producing a copy of the hard copy; said management means storing theadditional data extracted by said extraction means and managing saidprinter according to the additional data.
 33. The copy management systemto claim 32, wherein said management means further comprises a means forsumming the total number of copies derived from each original document.34. The copy management system according to claim 32, wherein saidadditional data comprises a data to identify said printer and a user andsaid management means further comprises a means for analyzing a tree mapon the generation of copies derived from the same original document. 35.An image forming apparatus comprising: a read means for reading an imageof a document; an image forming means for producing a copy according tothe image data read by said read means; a receive means for receiving anadditional data from a transmitter provided in the document, theadditional data comprising data on the management of copy; and a controlmeans for controlling the image forming means according to theadditional information received by said receive means.
 36. The imageforming apparatus according to claim 35, wherein said additional datacomprises a data to identify a document to be reproduced by said imageforming means and data to identify a user of said image forming means;said apparatus further comprising a decision means for deciding if thereproduction of the document is not legitimate from the receivedadditional data and inhibits the production of a copy of said imageforming means if said decision means decides that the reproduction isnot legitimate.
 37. The image forming apparatus according to claim 35,wherein said additional data comprises a data to identify a copy to bereproduced by said image forming means.
 38. The image forming apparatusaccording to claim 37, wherein said additional data further comprisesdata to identify said image forming apparatus and a user who operatessaid image forming apparatus.
 39. The image forming apparatus accordingto claim 37, wherein said additional data comprises a data on thegeneration of copy with respect to the original source.
 40. The imageforming apparatus according to claim 37, wherein said additional datacomprises a data to identify a sequential number of copies obtained fromthe same document.
 41. The image forming apparatus according to claim37, wherein said additional data comprises a data on the rank of secretof a document.